In one minute

Finazzi, Liberati and Barceló extend quantum corrections for warp drives from eternal bubbles at fixed speed to the more realistic case of a superluminal bubble created from initially flat spacetime. They map the causal structure of eternal and dynamical warp spacetimes and compute the renormalised stress-energy tensor of a quantum field in them. An observer at the centre of a superluminal bubble generically sees a thermal flux of Hawking particles, which becomes extremely high if the exotic matter comes from a quantum field obeying quantum inequalities. The stress-energy grows exponentially at the bubble's front wall, so these geometries are unstable to semiclassical backreaction.

Semiclassical instability of dynamical warp drives